1. Field of the Invention
The present intervention is an apparatus, such as an air knife or an air distribution manifold, for directing air under pressure at passing articles to dry or remove dust and debris from those articles.
2. Description of the Prior Art
Conventional air knives and air distribution manifolds are often formed as elongated structures that extend alongside or transverse to a conveyor belt or conveyor chain carrying articles to be dried or blown clean. Air knives are extensively used for drying a wide variety of articles of manufacture, such as plastic soft drink bottles prior to labeling, printed electronic circuit boards, food packaging, and many other products. Conventional pressure air delivery devices in the form of air knives and air nozzles have been used in a wide variety of industrial and commercial processes to remove or control the amount of liquids remaining on the surfaces of products after washing, rinsing, cooling, coating, or lubricating fluids have been applied. The same air delivery devices have also been used to blow dust and debris from products as well as to accelerate the heating or cooling of products. Applications for air knife and air nozzle blow off include printed circuit board assembly, machine parts, fabricated metals, plastic trays and totes, conveyor belts, electroplating, assorted textiles, food production and packaging, car and truck washing, and many other applications as well.
Conventional air knives and air distribution manifolds are usually mounted in a fixed orientation relative to a conveyor system past which articles to be dried or cleaned are carried. One disadvantage of conventional systems of this type is that the article to be dried or blown clean passes through the curtain of air being blown at it for only a very brief instant. Also, the flow of air of a conventional system is directed at the article to be treated from only a single direction. The configuration of the article is often such that “blind spots” are created on the portions of the article facing away from the oncoming airflow. These blind spots result from the fixed angle at which the airflow is directed against the product. Air velocity is much lower in these blind spots, thus reducing the drying or cleaning effect of the flowing air. As a consequence, the article is often inadequately dried or cleaned.
In order to achieve complete drying, multiple air knives, nozzles, and blowers have often been required. A conventional motor-driven rotary air knife must be coupled by a shaft, gear, chain, or belt to a drive motor. Such additional driving equipment increases both the cost and complexity of the air knife system.
Some conventional air knife systems have been designed to impart a rocking movement to the air knife duct or to otherwise vary the angle at which the air is directed toward the article. Other prior systems employ a motor to oscillate the air knife or nozzle in one plane so as to cause a lateral air blow off across the surface of a product. However, conventional devices of this type have been largely unsatisfactory. The effective area of coverage and the number of passes over the surface of products to be treated are quite limited as contrasted to the system of the present invention. Also, such conventional systems result in very slow product speeds of conveyance and sometimes even extended stationary product positioning to ensure adequate air blow off coverage of the product.